Hand-Held Grinding Machine and Method for Assembling a Hand-Held Grinding Machine

ABSTRACT

A hand-held grinding machine includes a grinding device for receiving or forming a grinding means, a drive device, a drive housing, and an interface device operatively connecting the grinding device to the drive device. The interface device includes a connecting housing unit formed separately from the drive housing and the grinding device for at least partially receiving the grinding device, and a docking interface arranged on the drive housing. The connecting housing unit engages around the docking interface in a fixing plane which is perpendicular to an axis of rotation of a drive shaft of the drive device. In the fixing plane, the docking interface includes at least one axial form-fitting element for forming a form fit with the connecting housing unit parallel to the axis of rotation. A projection of the axial form-fitting element along the axis of rotation is at least substantially inside the drive housing.

This application claims priority under 35 U.S.C. § 119 to application no. DE 10 2020 213 228.3, filed on Oct. 20, 2020 in Germany, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

U.S. Pat. No. 4,624,078 has already proposed a hand-held grinding machine having at least one grinding device for receiving or forming a grinding means, having a drive device for driving the grinding device, having a drive housing, which receives the drive device, and having an interface device for operatively connecting the grinding device to the drive device, wherein the interface device comprises at least one connecting housing unit, which is formed separately from the drive housing and the grinding device, for at least partially receiving the grinding device, and a docking interface arranged on the drive housing, wherein the connecting housing unit engages around the docking interface in a fixing plane which is perpendicular to an axis of rotation of a drive shaft of the drive device.

SUMMARY

The disclosure proceeds from a hand-held grinding machine having at least one grinding device for receiving or forming a grinding means, having a drive device for driving the grinding device, having a drive housing, which receives the drive device, and having an interface device for operatively connecting the grinding device to the drive device, wherein the interface device comprises at least one connecting housing unit, which is formed separately from the drive housing and the grinding device, for at least partially receiving the grinding device, and a docking interface arranged on the drive housing, wherein the connecting housing unit engages around the docking interface in a fixing plane which is perpendicular to an axis of rotation of a drive shaft of the drive device.

It is proposed that the docking interface in the fixing plane comprises at least one axial form-fitting element, which is in particular in the form of a fixing recess and/or oblique or concave surface, for forming a form fit with the connecting housing unit parallel to the axis of rotation, wherein a projection of the axial form-fitting element along the axis of rotation is at least substantially completely inside the drive housing. The hand-held grinding machine can preferably be held by a hand, in particular without a transporting and/or holding device, and can be guided and operated in particular with the same hand during a grinding operation. The hand-held grinding machine may be in the form of an eccentric grinder, a forcibly driven eccentric grinder, an oscillating grinder, a triangular grinder, a polisher, or the like. The grinding means may be in the form for example of abrasive paper, a grinding sponge pad, a non-open grinding fabric, a grinding cloth, a polishing sponge pad, a scrubbing wheel, a buffing wheel, or the like. In particular, the grinding device comprises at least one grinding pad having a planar basic area, which is in particular at least substantially parallel to the fixing plane and is provided for fastening the grinding means. “Provided” is to be understood to mean in particular specially configured, specially programmed, specially designed and/or specially equipped. An object being provided for a particular function should be understood in particular to mean that the object fulfils and/or carries out this particular function in at least one use state and/or operating state. “Substantially parallel” should be understood here in particular to mean an alignment of a direction relative to a reference direction, in particular in a plane, wherein the direction deviates in particular by less than 8°, advantageously less than 5° and especially advantageously less than 2° from the reference direction.

The drive device preferably comprises an electric motor, in particular a brushless DC motor, for driving the drive shaft, in particular about the axis of rotation common to the electric motor and the drive shaft. The drive device comprises in particular control electronics for the open-loop or closed-loop control of the electric motor. The drive device preferably comprises at least one electrical power supply interface for supplying energy to the electric motor. The electrical power supply interface is particularly preferably designed for receiving a battery which can be detached nondestructively from the drive device and/or a rechargeable battery, in particular a rechargeable battery pack, which can be detached nondestructively. As an alternative or in addition, the electrical power supply interface comprises a line-bound, inductive or capacitive charging element for supplying power to an internal energy store of the drive device.

The drive housing preferably comprises a longitudinal axis, which runs at least substantially perpendicular to the axis of rotation. A maximum longitudinal extent of the drive housing parallel to, in particular along, the longitudinal axis is preferably greater than an overall height of the drive housing parallel to, in particular along, the axis of rotation. Along the longitudinal axis, the drive housing comprises in particular a longitudinal-axis portion, in which the electrical power supply interface is arranged, and a front portion, in which the drive shaft is arranged. The docking interface is arranged in particular at the front portion along the axis of rotation. A maximum extent of a cross section of the longitudinal-axis portion perpendicular to the longitudinal axis is preferably smaller than the overall height of the drive housing, in particular such that the longitudinal-axis portion, the front portion and the docking interface form an L-shaped structure in an assembly plane. The assembly plane is spanned in particular by the longitudinal axis and by the axis of rotation.

The interface device is preferably provided to make available a standardized connection for the drive device and the grinding device, with the result that the drive device and the grinding device can be configured and/or pre-assembled in particular independently of one another. For example, a constructionally identical or analogous interface device in a further hand-held power tool connects a grinding device which is constructionally identical to that of the hand-held power tool to a drive device of a different power class to that of the hand-held power tool. For example, a constructionally identical or analogous interface device of an alternative hand-held power tool connects a different grinding device to that of the hand-held power tool to a drive device which is constructionally identical to that of the hand-held power tool. In particular, application-dependent gear mechanism elements for predefining a path of the grinding pad and/or application-dependent fastening elements for fastening the grinding pad relative to the drive housing are formed as part of the grinding device or the interface device.

In particular, the connecting housing unit is dependent on a configuration of the grinding device. The docking interface is preferably independent of a configuration of the grinding device and independent of a power class of the drive device. The docking interface is preferably formed in one piece with the drive housing. “In one piece” should in particular be understood as meaning shaped in one piece. This one piece is preferably produced from a single blank, a mass and/or a casting, particularly preferably in a pressing process, a die-casting process or an injection-molding process, in particular a single-component and/or multi-component injection-molding process. As an alternative, the docking interface is formed separately from the drive housing and is fastened to the drive housing. The docking interface preferably engages around the drive shaft in the fixing plane. The fixing plane preferably intersects the drive shaft. As an alternative, the drive shaft is set back along the axis of rotation relative to the docking interface, and therefore the fixing plane does not intersect the drive shaft. “For operatively connecting” should be understood in particular to mean for connecting in a manner that allows a transfer of mechanical work, for example by means of a coupling, by means of an eccentric gear mechanism, by means of a screw gear mechanism, by means of a toothed gear mechanism, and/or by means of another gear mechanism element. The interface device preferably comprises at least one gear mechanism element for indirectly or directly transferring a movement of the drive shaft to the grinding pad. The gear mechanism element of the interface device is preferably pressed on the drive shaft and/or latched in place on the drive shaft. As an alternative, the gear mechanism element of the interface device is formed in one piece with the drive shaft. The grinding device is preferably formed separately from the gear mechanism element and fastened to, in particular screwed on, pressed on and/or latched in place on, the gear mechanism element. As an alternative, the gear mechanism element of the interface device is formed in one piece with a gear mechanism element of the grinding device.

The connecting housing unit is provided in particular to enclose an intermediate space between the docking interface and the grinding pad, with a gear mechanism of the grinding device, a fan of the grinding device, or the like, for example, being arranged in said intermediate space. In particular, the connecting housing unit on a side facing the grinding pad has a groove for fastening a slip ring of the grinding device. The connecting housing unit is arranged on the docking interface by means of the axial form-fitting element in an immovable manner relative to the drive housing, in particular apart from a material elasticity of the connecting housing unit, the docking interface and/or the drive housing. The docking interface and the axial form-fitting element are provided in particular for a form-fitting and optionally force-fitting connection of the connecting housing unit to the drive housing. The connecting housing unit particularly preferably comprises at least two main shells, which are arranged against one another, in particular in the assembly plane. In particular, the main shells each engage partially around the docking interface in the fixing plane, in particular each around half of the docking interface in the fixing plane, from different sides of the docking interface. The main shells are preferably in the form of half-shells to be assembled. In particular, the connecting housing unit is arranged directly on the docking interface, in particular on an outer side, facing away from the axis of rotation, of the docking interface. The main shells preferably encapsulate the docking interface. It is preferably the case that at least a volume fraction of more than 50%, in particular more than 75%, particularly preferably more than 95%, of the docking interface is inside the connecting housing unit. In particular, the connecting housing unit is arranged in the fixing plane at an angular range with respect to the axis of rotation of more than 180°, preferably more than 270°, particularly preferably by more than 355°, around the docking interface. The connecting housing unit optionally comprises further housing elements, which are formed separately from the main shells. The main shells are preferably fastened by means of the axial form-fitting element to the docking interface and optionally to one another. The axial form-fitting element particularly preferably encloses a partial region of the connecting housing unit parallel to the axis of rotation inside a basic body of the docking interface and/or clamps in a partial region of the connecting housing unit between the docking interface and the drive housing. As an alternative, the docking interface comprises a structural element, which projects into a wall of the connecting housing unit.

The docking interface preferably comprises at least two, in particular two differently formed, axial form-fitting elements. The docking interface preferably has at least one pair of identically formed axial form-fitting elements, which are arranged in particular on different sides of a plane which encompasses the axis of rotation and is in particular perpendicular to the assembly plane. The entire docking interface is particularly preferably formed as mirror-symmetrical with respect to the plane which is perpendicular to the assembly plane and encompasses the axis of rotation. In particular, the assembly plane intersects the axial form-fitting element, in particular each of the axial form-fitting elements. The projections of all the axial form-fitting elements of the docking interface along the axis of rotation are particularly preferably at least substantially completely inside the drive housing. In particular, a projection of the entire docking interface along the axis of rotation is at least substantially completely inside the drive housing. “Substantially completely” should be understood to mean in particular at least up to 60%, preferably at least up to 80%, particularly preferably at least up to 95%, with respect to a maximum extent and/or a maximum surface area of the projection. An outer contour of the axial form-fitting element, in particular of the entire docking interface, in a projection along the axis of rotation is particularly preferably spaced apart, to a minimum extent inside the drive housing, from an outer contour of the drive housing by at least 3%, preferably more than 5%, with respect to a maximum extent of the projection.

The configuration according to the disclosure makes it possible to produce an advantageously secure connection between the drive housing and the connecting housing unit. In particular, a relative movement of the drive housing and the connecting housing unit can advantageously be kept small. In particular, the connecting housing unit is advantageously connected to the drive housing unit in an stable manner even when absorbing a force and/or a torque, for example caused by a hand or by additional components, for example a material collection container, arranged on the connecting housing unit. A transition between the drive housing and the connecting housing can also advantageously have a narrow configuration, with the result that a hand placed on the connecting housing unit can advantageously encompass the transition in a comfortable manner. In particular, an advantageously high operating comfort can be achieved.

It is also proposed that the docking interface, as axial form-fitting element, has a fixing recess, in particular a fixing recess which extends at least substantially parallel to the fixing plane and in particular a fixing recess which is provided to receive a fixing element of the connecting housing unit and/or a separately formed fixing element. The fixing element of the connecting housing unit is preferably integrally formed with one of the main shells and is in the form in particular of a structural element projecting from a contact surface of these main shells, for example a pin, a web, a latching tongue, or the like. The separately formed fixing element is in the form of a screw, a rivet, a threaded rod, a bar, or the like, for example. The docking interface preferably comprises the basic body, which in particular is solid. The fixing recess preferably extends in a direction at least substantially perpendicular to the axis of rotation, in particular to the assembly plane, into the basic body of the docking interface and particularly preferably through the basic body of the docking interface. As an alternative, the fixing recess is in the form of a blind hole, a groove, or the like. The expression “substantially perpendicular” should define here in particular an alignment of a direction relative to a reference direction, wherein the direction and the reference direction, in particular as viewed in a projection plane, forms an angle of 90° and the angle has a maximum deviation of in particular less than 8°, advantageously less than 5° and especially advantageously less than 2°. The basic body preferably completely engages around the fixing recess in the assembly plane. As an alternative, the basic body engages around the fixing recess in the assembly plane for example in a U-shape and forms in particular an assembly slot, which leads to the fixing recess and runs in particular in the fixing plane. The docking interface preferably comprises at least two fixing recesses, which are in particular constructionally identical and are arranged in the assembly plane on different sides of the axis of rotation. The configuration according to the disclosure advantageously makes it possible to easily obtain a form fit in both directions along the axis of rotation. In particular, the drive housing and the connecting housing unit are advantageously fixedly connected to one another. In particular, a number of fixing elements for fixing the connecting housing unit to an outer side of the connecting housing unit can advantageously be kept small. In particular, the connecting housing unit makes it possible to provide an advantageously large surface on which to place a hand.

It is also proposed that the connecting housing unit has at least two main shells, in particular those already mentioned, at least one of which comprises a fixing element in the form of a sleeve, in particular a fixing element in the form of a sleeve which is formed for receiving a separately formed fixing element, wherein an overall receiving length of the sleeve corresponds essentially to a length of the separately formed fixing element. The sleeve is preferably materially bonded to at least one of the main shells. The sleeve particularly preferably comprises two separately formed sleeve portions, one of which being arranged on one of the main shells in each case. In particular, the pair of sleeve portions is aligned one against the other along a fixing axis, with the result that the separate fixing element engages through both sleeve portions at the same time along the fixing axis. The sleeve is preferably arranged in the fixing recess of the docking interface. As an alternative, the sleeve is arranged outside the docking interface. That a parameter “corresponds substantially to a comparative parameter” should be understood in particular to mean that the parameter is equal to the comparative parameter by more than 25%, preferably more than 50%, particularly preferably more than 75%. The overall receiving length of the sleeve for receiving the fixing element is preferably shorter than the length of the fixing element. The sleeve portions are particularly preferably arranged spaced apart from one another along the fixing axis. In particular, one of the sleeve portions forms a blind hole, while the other sleeve portion is tubular. As an alternative, both sleeve portions are tubular. It is optionally the case that at least one of the sleeve portions forms a thread and/or a latching recess and/or comprises a recessed nut or another counterpiece to the separately formed fixing element. As an alternative, a counterpiece to the separately formed fixing element is arranged on an outer side of the docking interface. The configuration according to the disclosure with main shells advantageously makes it possible to easily assemble the connecting housing unit. In particular, the main shells can advantageously be clamped on the docking interface in addition to an axial form fit, with the result that an additional form and/or force fit at least substantially parallel to the axis of rotation can be obtained. A delimitation of the overall receiving length also makes it possible to obtain a fastening of the main shells to one another under tension, such that an advantageously tight contact of the main shells with the docking interface, an advantageously intense force fit of the main shells to the docking interface, and an advantageously small clearance of the main shells relative to the docking interface can be obtained.

It is furthermore proposed that the docking interface, as axial form-fitting element, has a docking cross section, which tapers along the axis of rotation in a direction away from the grinding device perpendicular to the axis of rotation. The docking cross section preferably tapers continuously in the direction of the axis of rotation over a portion which corresponds at least substantially to a docking height of the docking interface and comprises in particular more than 80% of the docking height of the docking interface. In particular, the docking cross section has the smallest extent parallel to the fixing plane on a side facing the drive housing. In particular, the docking cross section has the largest extent parallel to the fixing plane on a side facing away from the drive housing. In particular, the axial form-fitting element is in the form of the contact face, facing the drive housing and in particular facing away from the axis of rotation, of the docking interface. The contact surface preferably has an annular form, wherein a geometric central axis of the contact surface is aligned in particular coaxially with the axis of rotation. In particular, an inner wall of the housing connecting unit is arranged on the contact surface of the docking interface. A leadthrough in the housing connecting unit for receiving the drive shaft and/or the gear mechanism element of the interface device particularly preferably has a maximum opening width parallel to the fixing plane that is smaller than the maximum extent of the docking interface parallel to the fixing plane. In particular, the housing connecting unit is arranged between the drive housing and the docking interface, in particular the contact surface, on an axis parallel to the axis of rotation. A maximum extent of the docking cross section, in particular a largest external diameter of the docking interface, is preferably at least 10%, preferably more than 25%, particularly preferably more than 33% larger than a minimum extent, in particular a smallest external diameter, of the docking cross section parallel to the fixing plane. A smallest imaginary trapezium, which specifically completely surrounds the docking cross section of the docking interface, preferably has an acute inner angle between the base and the leg which is between 20° and 70°, preferably between 40° and 50°. The configuration according to the disclosure makes it possible to obtain an advantageously large contact surface on the docking interface for the connecting housing unit, which contact surface can be utilized as a clamping surface in particular in interaction with the fixing element when the connecting housing unit is being assembled. In particular, an advantageously large overlap between the connecting housing unit and the docking interface can be obtained.

It is additionally proposed that the docking interface, as axial form-fitting element, has an oblique and/or curved contact surface which runs transversely to the fixing plane, in particular that contact surface already mentioned, and has a form which is complementary to an in particular oblique and/or curved mating surface of the connecting housing unit. In particular, the contact surface, and in particular also the mating surface, intersects the fixing plane at an acute angle, in particular between 10° and 80°, preferably between 20° and 70°. When it has a curved configuration, the contact surface preferably has a concave form with respect to the axis of rotation. In particular, a radius of curvature which describes the concave contact surface runs outside the docking interface. As an alternative, the contact surface has a convex form with respect to the axis of rotation. In particular, a radius of curvature which describes the convex contact surface intersects the docking interface. In particular, the contact surface has at least one contact-surface portion which is formed in an arcuate manner in a plane, in particular any plane, containing the axis of rotation. At least one tangential plane of the contact surface preferably has an angle of less than 20°, preferably less than 15°, to the axis of rotation, wherein this tangential plane optionally has an angle of more than 5°, in particular more than 10°, to the axis of rotation. In particular, at least one further tangential plane of the contact surface has an angle of more than 90°, preferably more than 100°, particularly preferably more than 105%, to the axis of rotation, wherein this tangential plane optionally has an angle of less than 150°, in particular less than 125°, to the axis of rotation. In particular, a center-point angle of at least 35°, preferably at least 45°, in particular more than 55°, about a curvature center point which is part of the radius of curvature corresponds to an extent of the arcuate contact-surface portion. The contact surface in the direction of the grinding device preferably terminates with a planar contact portion, which is arranged tangentially to the curved contact portion of the contact surface. An arcuate extent of the contact surface is preferably longer, in particular at least twice as long, preferably more than three times as long, as the tangential continuation thereof in the planar contact portion. The configuration according to the disclosure advantageously makes it possible for the connecting housing unit to have a compact form. In particular, an advantageously large spacing of the connecting housing unit from the longitudinal-axis portion of the drive housing can be obtained, in particular such that it is possible to encompass the longitudinal-axis portion with a hand advantageously close to the axis of rotation. It is also advantageously possible for a hand placed on the connecting housing unit to advantageously also be placed between the longitudinal-axis portion and the connecting housing unit. In particular, an advantageously large number of grip positions is provided by the connecting housing unit.

It is additionally proposed that the radius of curvature amounts to between 5 mm and 15 mm. The radius of curvature is preferably greater than 7 mm, particularly preferably greater than 9 mm. The radius of curvature is preferably less than 12 mm, particularly preferably less than 10 mm. A ratio of the radius of curvature to the docking height of the docking interface parallel to the axis of rotation is preferably greater than 0.5, preferably greater than 0.7, and particularly preferably greater than 0.8. It is preferable for the ratio of the radius of curvature to the docking height of the docking interface parallel to the axis of rotation to be less than 1.5, preferably less than 1.2, particularly preferably less than 0.9. The configuration according to the disclosure makes it possible to advantageously configure the contact surface as compact and having a large surface area at the same time.

It is also proposed that the docking interface, in particular the contact surface, comprises at least 10% to 20%, in particular between 13% and 17%, of an overall height of the drive housing including the docking interface parallel to the axis of rotation. In an alternative configuration, the docking interface, in particular the contact surface, comprises between 5% and 10% or between 20% and 40% of an overall height of the drive housing including the docking interface parallel to the axis of rotation. The configuration according to the disclosure makes it possible to produce an advantageously stable connection between the drive housing and the connecting housing unit.

It is also proposed that the docking interface in the fixing plane engages around a bearing element of the drive device, in particular a bearing element of the drive device which is set up to rotatably mount a gear mechanism element, in particular the gear mechanism element already mentioned, of the interface device and/or the drive shaft. The bearing element is preferably in the form of a ball bearing, alternatively a sliding bearing. The bearing element is preferably arranged in the fixing plane between the fixing recesses of the docking interface. In particular, the fixing plane intersects the connecting housing unit and the bearing element. The gear mechanism element particularly preferably engages around the drive shaft in the fixing plane. The gear mechanism element optionally encompasses, on a side facing the electric motor, a larger cross section perpendicular to the axis of rotation than in the fixing plane, in particular a larger cross section than an opening width of the bearing element, for receiving the bearing element. The docking interface preferably has a groove, in which the bearing element is inserted or recessed. As an alternative, the drive shaft is in direct contact with the bearing element and in particular protrudes beyond the bearing element in the direction of the grinding device. The configuration according to the disclosure advantageously makes it possible for an overall height of the drive housing, in particular of the entire hand-held grinding machine, to be kept small. In particular, a fixed point on the axis of rotation can advantageously be established relative to the drive housing and relative to the connecting housing unit at the same time.

It is also proposed that the docking interface at a boundary, which is at least substantially perpendicular to the axis of rotation, to the drive housing, as axial form-fitting element, has a smaller cross section than the drive housing, and therefore the connecting housing unit can be arranged at least substantially flush with the drive housing on the docking interface. “Substantially flush” should be understood in particular to mean with an offset of less than 1 mm, preferably less than 0.75 mm, particularly preferably less than 0.5 mm. The drive housing together with the docking interface preferably forms an offset at the boundary. In particular, the drive housing at the boundary has a base surface, which is at least substantially parallel to the fixing plane and protrudes perpendicularly to the axis of rotation beyond the docking interface at the boundary in a manner corresponding to a material thickness of the housing connecting unit. In particular, the housing connecting unit is arranged on the offset and in particular continues a contour of the drive housing without any offset. The configuration according to the disclosure advantageously makes it possible to obtain a form fit counter to a direction established by the contact surface. In particular, an axial position of the connecting housing unit relative to the drive housing along the axis of rotation can be established with an advantageously low error tolerance. In particular, the risk of a compensating movement of the connecting housing unit in the direction of the drive housing, for example when the fixing element is being fastened and/or when the hand-held grinding machine is being pressed against a workpiece, can advantageously be kept low.

It is also proposed that the connecting housing unit has at least two main shells, in particular those already mentioned, which are aligned one against the other by means of at least one tongue and groove connection, which is in particular oblique or curved, in the fixing plane. In particular, one of the main shells has at least one groove and the other main shell has at least one tongue in the fixing plane, which groove and tongue are arranged one against the other in the assembly plane. The main shells preferably have at least one respective tongue and groove connection in the fixing plane on different sides of the axis of rotation. In particular, the tongue and groove connection is arranged in a curved contact portion of the main shells. The curved contact portion of the main shells forms in particular the mating surface which complements the contact surface. The contact portion preferably has an outer surface which is curved and faces away from the mating surface. A radius of external curvature is formed as smaller than the radius of curvature of the contact surface and is arranged in particular outside the main shell. In particular, the main shells comprise a tangential portion which has a planar form and continues the curved contact portion tangentially beyond the docking interface. The tongue and groove connection is preferably arranged in a transition region between the tangential portion and the contact portion of the main shells. It is preferable that a ratio of a transverse extent of the tongue and groove connection parallel to a material thickness of the main shells to the material thickness of the main shells is greater than 0.15, preferably greater than 0.2, and in particular greater than 0.25. The transverse extent of the tongue and groove connection is preferably between 0.5 mm and 1.5 mm, particularly preferably between 0.75 mm and 1 mm. Optionally, the connecting housing unit between the main shells comprises an elastic sealing element. The tongue and groove connection is preferably formed as convex, alternatively concave, with respect to the axis of rotation. In particular, a connecting surface of the tongue and groove connection runs at least substantially parallel to the mating surface of the connecting housing unit. The configuration according to the disclosure advantageously makes it possible to obtain an additional, mutual form fit parallel to the axis of rotation and also a frictional engagement in the fixing plane of the main shells. In particular, the main shells can advantageously be arranged against one another in a simple and precise manner. In particular, the main shells, in particular by contrast with a stepped rebate, can advantageously be arranged against one another under tension by means of the fixing element.

It is furthermore proposed that a drive fan of the drive device and a fan of the grinding device are arranged along the axis of rotation on different sides of the axial form-fitting element. In particular, the drive fan is in the form of a motor fan. The drive fan is in particular provided to cool the electric motor. In particular, the fan is arranged inside the connecting housing unit. The drive fan is preferably arranged in the drive housing. The docking interface is preferably arranged between the drive fan and the fan. The docking interface preferably delimits a receiving space in the drive housing for the drive fan. The docking interface preferably delimits a fan receiving region of the connecting housing unit for the fan. In particular, the drive fan and the fan are arranged at ends, facing away from one another, of the gear mechanism element of the interface device. In particular, the gear mechanism element projects into the receiving space for the drive fan and into the fan receiving region for the fan. The gear mechanism element of the interface device is provided in particular to drive the fan. The gear mechanism element of the interface device is in particular provided to support an axial position of the drive fan along the drive shaft. The configuration according to the disclosure advantageously makes it possible to design the docking interface and in particular the drive device independently of the specific grinding device. In particular, the docking interface can be designed independently of a dimensioning of the grinding device, in particular the fan. In particular, the docking interface may be utilized in addition to an aerodynamic separation of the drive fan and the fan, with the result that the hand-held grinding machine can advantageously be configured as compact.

The disclosure additionally proceeds from a method for assembling a hand-held grinding machine having at least one grinding device for receiving or forming a grinding means, having a drive device for driving the grinding device, which drive device in at least one method step is arranged in a drive housing of the hand-held grinding machine, and having an interface device for operatively connecting the grinding device to the drive device, wherein the interface device comprises at least one connecting housing unit, which is formed separately from the drive housing and the grinding device and in which in at least one method step the grinding device is at least partially arranged, and a docking interface arranged on the drive housing, wherein in at least one method step the connecting housing unit is arranged so as to engage around the docking interface in a fixing plane which is perpendicular to an axis of rotation of a drive shaft of the drive device. It is proposed that in at least one method step, in which a form fit, parallel to the axis of rotation, of the connecting housing unit to the docking interface is formed by means of an axial form-fitting element of the docking interface that is arranged in the fixing plane and in the form in particular of a fixing recess and/or oblique or concave surface, wherein a projection of the axial form-fitting element along the axis of rotation is at least substantially completely inside the drive housing. In at least one method step, the gear mechanism element of the interface unit is preferably pressed onto the drive shaft of the drive device, which in particular is pre-assembled. In at least one method step, the grinding device, which in particular is pre-assembled, is preferably fastened, in particular screwed, to the gear mechanism element. In at least one method step, one of the main shells is preferably arranged on the docking interface. In particular, the mating surface is arranged on the contact surface. In particular, the sleeve portion of the main shell is inserted into the fixing recess of the docking interface. In at least one method step, a further one of the main shells is preferably arranged on the docking interface, in particular the main shells are arranged against one another in the assembly plane and in particular aligned against one another by means of the tongue and groove connection. The mating surface of the further one of the main shells is in particular arranged on the contact surface.

The sleeve portion of the further one of the main shells is inserted into the fixing recess. In particular, in at least one method step the separately formed fixing element is plugged, pressed or screwed through one of the main shells, the sleeve and the docking interface into a further one of the main shells. The configuration according to the disclosure makes it possible to advantageously produce the hand-held grinding machine in a modular manner and to advantageously assemble it in a simple manner. In particular, it is possible to achieve a high degree of flexibility in terms of a combination of a drive device, which is in particular standardized, and one of a variety of grinding devices. In particular, an advantageously high stability of the hand-held grinding machine can be achieved despite a modular structure.

The grinding machine according to the disclosure and/or the method according to the disclosure are not intended to be limited to the above-described application and embodiment in this respect. In particular, the grinding machine according to the disclosure and/or the method according to the disclosure may have a number of individual elements, components and units and of method steps which differs from the number thereof stated herein for the purpose of satisfying a mode of operation described herein. Moreover, for the value ranges specified in this disclosure, values that also lie within the stated limits should also be considered to be disclosed and usable in any desired way.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages will become apparent from the following description of the drawing. Four exemplary embodiments of the disclosure are illustrated in the drawings. The drawings, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them to form useful further combinations.

In the figures:

FIG. 1 shows a schematic perspective illustration of a hand-held grinding machine according to the disclosure,

FIG. 2 shows a schematic plan view of the hand-held grinding machine according to the disclosure,

FIG. 3 shows a schematic longitudinal section of the hand-held grinding machine according to the disclosure,

FIG. 4 shows a schematic cross section of the hand-held grinding machine according to the disclosure,

FIG. 5 shows a schematic illustration of a fastening of a connecting housing unit of the hand-held grinding machine according to the disclosure,

FIG. 6 shows a schematic cross section of the connecting housing unit,

FIG. 7 shows a schematic longitudinal section of a material collection device of the hand-held grinding machine according to the disclosure,

FIG. 8 shows a schematic flow diagram of a method according to the disclosure for assembling the hand-held grinding machine according to the disclosure,

FIG. 9 shows a schematic illustration of an alternative configuration of a hand-held grinding machine according to the disclosure with an alternative drive device,

FIG. 10 shows a schematic longitudinal section of the alternative configuration,

FIG. 11 shows a schematic illustration of a further alternative configuration of a hand-held grinding machine according to the disclosure with an alternative grinding device,

FIG. 12 shows a schematic longitudinal section of the further alternative configuration,

FIG. 13 shows a schematic illustration of a further alternative configuration of a hand-held grinding machine according to the disclosure with a further alternative grinding device, and

FIG. 14 shows a schematic longitudinal section of the additional alternative configuration.

DETAILED DESCRIPTION

FIG. 1 shows a hand-held power tool 118 a in the form of a hand-held grinding machine 10 a. The hand-held grinding machine 10 a is in the form in particular of an eccentric grinder. The hand-held grinding machine 10 a comprises a grinding device 12 a for receiving a grinding means 13 a. The grinding device 12 a comprises in particular a grinding pad 132 a, which is illustrated here by way of example with a diameter of 125 mm. As an alternative, the grinding pad 132 a has a diameter of 150 mm or another diameter which is adapted to a size of the grinding means 13 a. The hand-held grinding machine 10 a comprises a drive device 14 a for driving the grinding device 12 a (see FIG. 4), which drive device in particular defines an axis of rotation 24 a about which the grinding pad 132 a can be driven, in particular eccentrically. The hand-held grinding machine 10 a comprises a drive housing 16 a, which receives the drive device 14 a.

The drive housing 16 a has a longitudinal axis 92 a, which runs at least substantially perpendicular to the axis of rotation 24 a. The drive housing 16 a preferably has two drive housing half-shells, which are arranged against one another in an assembly plane 50 a which is spanned by the longitudinal axis 92 a and the axis of rotation 24 a (cf. FIG. 2). The drive housing 16 a comprises a longitudinal-axis portion 90 a, which is arranged around the longitudinal axis 92 a. The longitudinal-axis portion 90 a is provided in particular for receiving a rechargeable battery pack 138 a, in particular a 12 volt rechargeable battery pack. The drive housing 16 a has a front portion 94 a. The front portion 94 a surrounds an intersection point region of the axis of rotation 24 a and the longitudinal axis 92 a. The front portion 94 a comprises a dome-shaped grip surface 96 a. The grip surface 96 a is optionally in the form of a soft component, which is arranged, in particular recessed, on a housing basic body of the drive housing 16 a. As an alternative, an outer surface of the housing basic body of the drive housing 16 a forms the grip surface 96 a. The hand-held grinding machine 10 a comprises at least one actuating element 88 a for controlling the drive device 14 a, in particular for switching the drive device 14 a on and off. The actuating element 88 a is preferably able to be latched in place in an activated state of the drive device 14 a. The actuating element 88 a is arranged in the grip surface 96 a. The actuating element 88 a is arranged on a side, facing away from the longitudinal-axis portion 90 a, of a plane which is perpendicular to the longitudinal axis 92 a and encompasses the axis of rotation 24 a.

The hand-held grinding machine 10 a comprises an interface device 18 a for operatively connecting, in particular for coupling, the grinding device 12 a to the drive device 14 a. The interface device 18 a is arranged in particular along the axis of rotation 24 a on the front portion 94 a. The interface device 18 a comprises at least one connecting housing portion 20 a for at least partially receiving the grinding device 12 a. The connecting housing unit 20 a is formed separately from the drive housing 16 a and the grinding device 12 a. The connecting housing unit 20 a has at least two main shells 46 a, 48 a. The main shells 46 a, 48 a are arranged in particular against one another in the assembly plane 50 a. The main shells 46 a, 48 a are preferably manufactured from plastic. The main shells 46 a, 48 a preferably have a wall thickness of between 1 mm and 3.5 mm, preferably between 1.5 mm and 2.5 mm, particularly preferably between 1.9 mm and 2.3 mm. The connecting housing unit 20 a comprises an ejection port 76 a. The ejection port 76 a is provided in particular for ejecting material that has been worn off during a grinding process from the connecting housing unit 20 a. The ejection port 76 a is preferably arranged on one of the main shells 46 a. The hand-held grinding machine 10 a comprises a material collection device 116 a. The material collection device 116 a comprises a material collection container 112 a, which is preferably air-impermeable, for collecting material, such as in particular dust, chips and/or grit, which has been removed during operation of the hand-grinding machine 10 a, and in particular ejected via the ejection port 76 a. In at least one configuration of the material collection container 112 a, a container longitudinal axis 114 a of the material collection container 112 a runs at least substantially parallel to the longitudinal axis 92 a of the drive housing 16 a. In particular, the container longitudinal axis 114 a is in the form of a container center axis, which runs in particular through a geometric center of gravity of the material collection container 122 a.

FIG. 2 shows a view of the hand-held grinding machine 10 a along the axis of rotation 24 a. The drive housing 16 a has a protrusion 102 a, 104 a to either side of a plane which is perpendicular to the axis of rotation 24 a and encompasses the longitudinal axis 92 a. A ratio of a maximum protrusion transverse extent 107 a of the protrusion 102 a to that of the protrusion 104 a of the drive housing 16 a relative to a largest grip-surface transverse extent 106 a of the front portion 94 a is between 0.75 and 0.9, in particular between 0.80 and 0.85. The largest grip-surface transverse extent 106 a is preferably at the same time the largest transverse extent of the drive housing 16 perpendicular to the axis of rotation 24 a and perpendicular to the longitudinal axis 92 a. The largest grip-surface transverse extent 106 a amounts, in relation to an overall height 54 a (cf. FIGS. 3 and 4) of the drive housing 16 a, to preferably between 0.8 and 0.95, in particular between 0.85 and 0.9. The largest grip-surface transverse extent 106 a preferably amounts to between 65 mm and 85 mm, in particular between 70 mm and 80 mm. In particular, the overall height 54 a of the drive housing 16 a parallel to the axis of rotation 24 a is smaller than 95 mm, preferably smaller than 90 mm, in particular smaller than 85 mm. A maximum machine height parallel to the axis of rotation 24 a of the hand-held grinding machine 10 a is particularly preferably smaller than 115 mm, in particular smaller than 110 mm.

The grip surface 96 a of the drive housing 16 a transitions, proceeding from the front portion 94 a, continuously in the direction of the longitudinal axis 92 a into a tapering region 108 a, delimited by the protrusions 102 a, 104 a, of the longitudinal-axis portion 90 a. A ratio of a maximum tapering transverse extent 110 a of the tapering region 108 a to the largest grip-surface transverse extent 106 a of the front portion 94 a is between 0.7 and 0.85, in particular between 0.75 and 0.8. The grip surface 96 a of the drive housing 16 a extends from the front portion 94 a to a plane which is perpendicular to the longitudinal axis 92 a and intersects the protrusions 102 a, 104 a. The grip surface 96 a optionally extends along the longitudinal axis 92 a over the protrusions 102 a, 104 a. A plane which is perpendicular to the longitudinal axis 92 a and intersects the protrusions 102 a, 104 a, subdivides a maximum longitudinal extent 111 a, 113 a of the drive housing 16 a in a ratio of between 0.45 and 0.65. In particular, a ratio of a protrusion position 139 a of the plane, intersecting the protrusions 102 a, 104 a, along the longitudinal axis 92 a proceeding from a point of the front portion 94 a that is furthest away from the maximum longitudinal extent 111 a without a rechargeable battery pack 138 a amounts to between 0.55 and 0.60. In particular, a ratio of a protrusion position 139 a of the plane, intersecting the protrusions 102 a, 104 a, along the longitudinal axis 92 a proceeding from a point of the front portion 94 a that is furthest away from the maximum longitudinal extent 113 a including a rechargeable battery pack 138 a amounts to between 0.5 and 0.55. In particular, the maximum longitudinal extent 111 a, 113 a parallel to, in particular along, the longitudinal axis 92 a is greater than the overall height 54 a of the drive housing 16 a.

The material collection container 112 a is arranged spaced apart from the grip surface 96 a of the drive housing 16 a in a plane which is perpendicular to the axis of rotation 24 a. In particular, the material collection container 112 a is arranged only on the ejector port 76 a by means of an assembly unit 124 a of the material collection device 116 a, in particular in a suspended manner and in particular without further support elements. A transition between the assembly unit 124 a and the material collection container 112 a is arranged in a plane which is perpendicular to the longitudinal axis 92 a with the tapering region 108 a. A channel longitudinal axis 84 a of the ejector port 76 a of the connecting housing unit 20 a is aligned at an acute angle, in particular between 40° and 50°, preferably between 44° and 46°, to the longitudinal axis 92 a in a plane which is perpendicular to the axis of rotation 24 a. The channel longitudinal axis 84 a is preferably in the form of a channel center axis, which runs in particular through a geometric center of gravity of the ejector port 76 a. The hand-held grinding machine 10 a has an operating element 117 a, in particular one which is different from the actuating element 88 a, for controlling the grinding device 12 a (cf. FIG. 1), for example for matching a rotational speed of the grinding pad 132 a. For example, the operating element 117 a is in the form of a rotary controller. The operating element 117 a and the material collection container 112 a are arranged on different sides of the assembly plane 50 a spanned by the axis of rotation 24 a and the longitudinal axis 92 a. The drive housing 16 a has a spacing from the material collection container 112 a which is between 10 mm and 40 mm, preferably between 15 mm and 35 mm, particularly preferably between 20 mm and 30 mm. The operating element 117 a is preferably arranged in the tapering region 108 a. The operating element 117 a and the actuating element 88 a are preferably arranged on different sides of a transverse plane 98 a which is perpendicular to the axis of rotation 24 a and in which the front portion 94 a has the largest grip-surface transverse extent 106 a.

FIG. 3 shows a longitudinal section of the hand-held grinding machine 10 a in the assembly plane 50 a and FIG. 4 shows a cross section of the hand-held grinding machine 10 a. The grinding device 12 a preferably comprises an eccentric, which is driven by a drive shaft 26 a. The grinding device 12 a preferably comprises an eccentric bearing 158 a, which is in particular in the form of a ball bearing. The eccentric bearing 158 a optionally comprises a plurality of ball bearings, which are in particular stacked one on top of another along the axis of rotation 24 a, or a multi-row, in particular two-row, ball bearing. The eccentric bearing 158 a is arranged in particular on the eccentric and engages around the eccentric preferably in a plane which is perpendicular to the axis of rotation 24 a. The eccentric bearing 158 a is clamped on an offset of the eccentric, in particular by means of an assembly plate and a screw. In particular, a geometric center point of the eccentric bearing 158 a is arranged spaced apart from the axis of rotation 24 a. In particular, the grinding device 12 a comprises an annular grinding-pad holder 156 a. The grinding-pad holder 156 a is arranged on the eccentric bearing 158 a and engages around it preferably in a plane which is perpendicular to the axis of rotation 24 a. The grinding-pad holder 156 a preferably has a groove, in which the eccentric bearing 158 a is arranged. The eccentric bearing is particularly preferably formed such that it is injection molded around the grinding-pad holder 156 a. In particular, the grinding-pad holder 156 a can be rotated relative to the eccentric. The grinding pad 132 a is preferably fastened to the grinding-pad holder 156 a, in particular screw-connected in a direction parallel to the axis of rotation 24 a. In particular, the grinding device 12 a optionally comprises a fan 66 a. In particular, the fan 66 a is operated by the drive shaft 26 a. A blading of the fan 66 a preferably surrounds the grinding-pad holder 156 a in a plane which is perpendicular to the axis of rotation 24 a, wherein the grinding-pad holder 156 a projects beyond the fan 66 a in a direction of the axis of rotation 24 a. The grinding device 12 a preferably comprises a slip ring 154 a of an elastic material, which slip ring is fastened in a rotationally fixed manner to the connecting housing unit 20 a on the connecting housing unit 20 a in a groove, and in particular rests on the grinding pad 132 a, in particular in order to stabilize a rotational movement of the grinding pad 132 a.

The drive device 14 a preferably comprises an electric motor 134 a. In particular, the electric motor 134 a incorporates a rated voltage of 12 volts. The drive device 14 a comprises the drive shaft 26 a, which is driven in particular by the electric motor 134 a about the axis of rotation 24 a. In particular, the drive device 14 a comprises an electrical power supply interface 136 a, in particular for connecting the rechargeable battery pack 138 a. The drive device 14 a preferably comprises at least one set of control electronics 140 a, in particular for controlling the electric motor 134 a. The electric motor 134 a, the control electronics 140 a and the electrical power supply interface 136 a are preferably arranged along the longitudinal axis 92 a, in particular in this order. In particular, the electric motor 134 a is arranged in the front portion 94 a. In particular, the control electronics 140 a are arranged in the tapering region 108 a. In particular, the electrical power supply interface 136 a is arranged in the longitudinal-axis portion 90 a. The drive shaft 26 a preferably protrudes proceeding from the front portion 94 a into the interface device 18 a.

The actuating element 88 a is arranged, in particular recessed, in a partial surface area, arranged obliquely to the longitudinal axis 92 a and to the axis of rotation 24 a, of the grip surface 96 a. The partial surface area which receives the actuating element 88 a preferably has an angle of between 40° and 50° to the longitudinal axis 92 a. A projection of the actuating element 88 a along the axis of rotation 24 a in particular does not overlap the electric motor 134 a. The actuating element 88 a and the grinding device 12 a are arranged on different sides of the transverse plane 98 a which is at least substantially perpendicular to the axis of rotation 24 a and in which the front portion 94 a has the largest grip-surface transverse extent 106 a. In particular, more than half, preferably more than 66%, particularly preferably more than 75%, of a volume of the electric motor 134 a is arranged on that side of the transverse plane 98 a which is opposite the actuating element 88 a. Between 40% and 60% of a volume of a receiving region of the electrical power supply interface 136 a for receiving the rechargeable battery pack 138 a is preferably arranged on that side of the transverse plane 98 a which is opposite the actuating element 88 a. In particular, the partial surface area, surrounding the actuating element 88 a, of the grip surface 96 a is flattened, in particular has a planar form in sections, in the assembly plane 50 a. The front portion 94 a in the transverse plane 98 a preferably has a continuously curved profile. Partial surface areas of the grip surface 96 a, one of which surrounds the actuating element 88 a and which terminate the front portion 94 a along the longitudinal axis 92 a, are arranged at a front angle 142 a of between 95° and 110° to one another. The front angle 142 a is in particular in the assembly plane 50 a. In particular, the partial surface areas terminating the front portion 94 a are arranged on different sides of the transverse plane 98 a which has the largest grip-surface transverse extent 106 a and runs perpendicular to the axis of rotation 24 a.

A ratio of a maximum grip-surface height 100 a, parallel to the axis of rotation 24 a, of the grip surface 96 a to the overall height 54 a, parallel to said maximum grip-surface height, of the drive housing 16 a, is between 0.65 and 0.8 and preferably between 0.7 and 0.75. In particular, the grip surface 96 a extends in a direction of the axis of rotation 24 a as far as an end of the electric motor 134 a that faces the grinding device 12 a. The drive device 14 a preferably comprises a drive fan 64 a, in particular for cooling the electric motor 134 a. The drive fan 64 a is arranged on the axis of rotation 24 a between the electric motor 134 a and the interface device 18 a. The grip surface 96 a preferably extends in a direction of the axis of rotation 24 a as far as a fan portion 144 a of the drive housing 16 a, in which ventilation openings for sucking in and/or blowing out air through the drive fan 64 a are arranged. The grip-surface height 100 a preferably decreases, in particular continuously, in a direction of the longitudinal axis 92 a (cf. also FIG. 5). The drive fan 64 a and the longitudinal-axis portion 90 a are preferably arranged, in particular completely, on different sides of a plane which is perpendicular to the axis of rotation 24 a. The front portion 94 a preferably tapers in a direction of the axis of rotation 24 a to the fan portion 144 a. In particular, the actuating element 88 a projects along the longitudinal axis 92 a at least partially beyond the fan portion 144 a. A unit composed of the drive housing 16 a and the connecting housing unit 20 a preferably has, on the fan portion 144 a, a cross section, perpendicular to the axis of rotation 24 a, between the actuating element 88 a and the grinding device 12 a that has the smallest surface area. In particular, the fan portion 144 a has a maximum transverse extent perpendicular to the axis of rotation 24 a of less than 65 mm, preferably less than 60 mm, particularly preferably less than 55 mm.

The interface device 18 a comprises a docking interface 22 a, which is arranged on the drive housing 16 a. The connecting housing unit 20 a engages around the docking interface 22 a in a fixing plane 27 a perpendicular to the axis of rotation 24 a of the drive shaft 26 a of the drive device 14 a. The docking interface 22 a has, in the fixing plane 27 a, at least one axial form-fitting element 28 a, 29 a, 30 a, 32 a for forming a form fit, parallel to the axis of rotation 24 a, with the connecting housing unit 20 a. A projection of the axial form-fitting element 28 a, 29 a, 30 a, 32 a along the axis of rotation 24 a is at least substantially completely inside the drive housing 16 a. In particular, the docking interface 22 a comprises a plurality of axial form-fitting elements 28 a, 29 a, 30 a, 32 a, the projections of which along the axis of rotation 24 a are at least substantially completely inside the drive housing 16 a. In particular, a projection of the entire docking interface 22 a is at least substantially completely inside the drive housing 16 a. The docking interface 22 a is preferably arranged along the axis of rotation 24 a on the front portion 94 a. In particular, the fan portion 144 a is arranged between the front portion 94 a and the docking interface 22 a. The docking interface 22 a is preferably materially bonded to the drive housing 16 a. In particular, the overall height 54 a of the drive housing 16 a refers to an extent which is parallel to the axis of rotation 24 a and also includes the docking interface 22 a.

The docking interface 22 a, as axial form-fitting element 30 a, 32 a, comprises a fixing recess 34 a, 36 a. The fixing recess 34 a, 36 a preferably extends at least substantially parallel to the fixing plane 27 a. In particular, the fixing recess 34 a, 36 a is provided to receive a fixing element 38 a, 40 a of the connecting housing unit 20 a and a separately formed fixing element 42 a, 44 a. The fixing element 38 a, 40 a of the connecting housing unit 20 a is in the form of a sleeve, particularly preferably a screw boss. The sleeve is designed to receive the separately formed fixing element 42 a, 44 a. The separately formed fixing element 42 a, 44 a is preferably in the form of a screw. An overall receiving length of the sleeve corresponds in particular substantially, but in particular not completely, to a length of the separately formed fixing element 42 a, 44 a. In particular, the sleeve comprises two sleeve portions, one of which is arranged on each of the two main shells 46 a, 48 a, with the result that there is an air gap between the two sleeve portions. In particular, the main shells 46 a, 48 a are fastened to the docking interface 22 a under tension by tightening the separately formed fixing element 42 a, 44 a in the sleeve. In particular, the separately formed fixing element 42 a, 44 a engages in, and in particular through, the docking interface 22 a. In the fixing plane 27 a, the docking interface 22 a preferably comprises at least two, in particular exactly two, copies of the fixing element 38 a, 40 a per main shell 46 a, 48 a and in particular at least two, in particular exactly two, copies of the separately formed fixing element 42s, 44 a, which are arranged in particular on different sides of a plane which is perpendicular to the longitudinal axis 92 a and encompasses the axis of rotation 24 a. The connecting housing unit 20 a optionally comprises at least one additional fixing element 150 a, 152 a, which is provided to fasten the main shells 46 a, 48 a to one another at a position spaced apart from the fixing plane 27 a. The connecting housing unit 20 a preferably comprises at least two additional fixing elements 150 a, 152 a, which are arranged in particular between the fixing plane 27 a, in particular between an end of the docking interface 22 a which faces the grinding pad 132 a and the grinding pad 132 a. In particular, the additional fixing elements 150 a, 152 a are in the form of screws. Additional fixing recesses for the main shells 46 a, 48 a for receiving the additional fixing elements 150 a, 152 a are preferably arranged in a plane which is parallel to the fixing plane 27 a and comprises the greatest transverse extent of the connecting housing unit 20 a in the assembly plane 50 a.

Perpendicular to the axis of rotation 24 a, the docking interface 22 a, as axial form-fitting element 28 a, encompasses a docking cross section which tapers along the axis of rotation 24 a in a direction away from the grinding device 12 a and in particular leading toward the fan portion 144 a. In particular, the fixing recess 34 a, 36 a is arranged between a maximum cross section of the docking interface 22 a perpendicular to the axis of rotation 24 a and a minimum cross section of the docking interface 22 a perpendicular to the axis of rotation 24 a. The docking interface 22 a preferably comprises a contact surface 52 a, which is formed on a surface of the docking interface 22 a that forms the taper. The contact surface 52 a faces away in particular from the grinding device 12 a and faces in particular the drive device 14 a. The main shells 46 a, 48 a have in particular a mating surface, complementary to the contact surface 52 a, on one of their respective inner walls. The mating surfaces of the main shells 46 a, 48 a are arranged in particular on the contact surface 52 a and particularly preferably pressed against the contact surface 52 a over their surface area by means of the fixing elements 42 a. At a boundary, which is at least substantially perpendicular to the axis of rotation 24 a, to the drive housing 16 a, in particular to the fan portion 144 a, the docking interface 22 a, as axial form-fitting element 29 a, has a smaller cross section than the drive housing 16 a. In particular, a difference in the cross sections of the docking interface 22 a and of the drive housing 16 a at the boundary corresponds to a wall thickness, in particular twice the wall thickness, of the connecting housing unit 20 a. A portion of the main shells 46 a, 48 a which forms the mating surfaces extends preferably along the contact surface to the boundary. The connecting housing unit 20 a is arranged at least substantially flush with the drive housing 16 a on the docking interface 22 a. The docking interface 22 a, in particular the contact surface 52 a, encompasses at least 10% to 20% of the overall height 54 a of the drive housing 16 a including the docking interface 22 a parallel to the axis of rotation 24 a. It is preferably the case that a ratio of a docking height of the docking interface 22 a parallel to the axis of rotation to a maximum transverse extent, in particular a maximum diameter, of the docking interface 22 a perpendicular to the axis of rotation is between 0.1 and 0.3, preferably between 0.15 and 0.2. It is preferably the case that a ratio of the docking height of the docking interface 22 a parallel to the axis of rotation to a minimum transverse extent, in particular a minimum diameter, of the docking interface 22 a perpendicular to the axis of rotation 24 a is between 0.15 and 0.35, preferably between 0.2 and 0.25. It is preferably the case that a spacing parallel to the axis of rotation 24 a between the maximum transverse extent and the minimum transverse extent of the docking interface 22 a perpendicular to the axis of rotation 24 a corresponds to at least 60%, preferably more than 75%, of the docking height.

The contact surface 52 a runs transversely to the fixing plane 27 a and has a curved form. The mating surface has a curvature which complements the contact surface 52 a. The curvature of the contact surface 52 a and in particular of the mating surface preferably have a concave form with respect to the axis of rotation 24 a. A radius of curvature which describes the contact surface 52 a and in particular the mating surface runs outside the docking interface 22 a and in particular through the connecting housing unit 20 a. The radius of curvature amounts to between 5 mm and 15 mm, preferably between 9 mm and 10 mm. A curvature center point which is part of the radius of curvature preferably lies outside the connecting housing unit 20 a. The wall thickness of the connecting housing unit 20 a optionally decreases along the curvature in the direction of the drive housing 16 a. As an alternative, the wall thickness of the connecting housing unit 20 a is constant along the curvature. The contact surface 52 a preferably encompasses a planar contact portion, which continues the curvature of the docking interface 22 a tangentially in the direction of the grinding pad 132 a. In particular, the planar contact portion of the contact surface 52 a is inclined with respect to the fixing plane 27 a at an angle of between 10° and 20° in the direction of the grinding pad 132 a. A portion of the main shells 46 a, 48 a that forms the mating surfaces preferably extends over the planar contact portion, in particular at the same angle to the fixing plane 27 a as the planar contact portion of the contact surface 52 a. This extent of the main shells 46 a, 48 a continues in particular as far as one end of the connecting housing unit 20 a in this direction or as far as the additional fixing recesses or as far as the ejector port 76 a. In particular, a top side, facing the drive device 14 a, of the main shells 46 a, 48 a forms a hand placement surface, which is inclined in particular relative to the grinding pad 132 a and falls away in particular outward from the axis of rotation 24 a, in particular for supporting natural holding in the hand when thumb and index finger are arranged on different sides of the axis of rotation 24 a. The main shells 46 a, 48 a are aligned against one another by means of a tongue and groove connection 60 a, 62 a, which is in particular curved, of the housing unit 20 a in the fixing plane 27 a.

FIG. 5 illustrates the interface device 18 a without one of the main shells 48 a. The docking interface 22 a has, as basic body, in particular a rotary body with respect to the axis of rotation 24 a. As an alternative, the basic body of the docking interface 22 a extends parallel to the longitudinal axis 92 a and has in particular an elliptical or tapering cross section perpendicular to the axis of rotation 24 a. The docking interface 22 a has, recessed in the basic body, depressions, access shafts, in particular for the sleeve of the main shells 46 a, 48 a and the separately formed fixing element 42 a, 44 a, and/or ventilation openings.

It can also be seen from FIGS. 3 and 4 that the interface device 18 a comprises a gear mechanism element 58 a. The gear mechanism element 58 a of the interface device 18 a is in the form in particular of an eccentric shank. The gear mechanism element 58 a of the interface device 18 a is preferably formed separately from the drive device 14 a and the grinding device 12 a. The gear mechanism element 58 a of the interface device 18 a is preferably pressed on the drive shaft 26 a along the axis of rotation 24 a and in particular connected to the drive shaft 26 a for rotation therewith. The eccentric, in particular together with the already mentioned assembly plate, is preferably screwed on the gear mechanism element 58 a of the interface device 18 a and in particular connected to the gear mechanism element 58 a of the interface device 18 a for rotation therewith. As an alternative, the gear mechanism element 58 a is formed integrally with the drive shaft 26 a or with the eccentric of the grinding device 12 a.

The docking interface 22 a engages around a bearing element 56 a of the drive device 14 a in the fixing plane 27 a, which bearing element is configured for rotatably mounting the gear mechanism element 58 a of the interface device 18 a. The drive shaft 26 a preferably extends along the axis of rotation 24 a into the bearing element 56 a, in particular through the bearing element 56 a. The gear mechanism element 58 a preferably surrounds the drive shaft 26 a in the fixing plane 27 a, such that the drive shaft 26 a in particular is not in direct contact with the bearing element 56 a. In particular, the bearing element 56 a is in the form of a ball bearing. The gear mechanism element 58 a of the interface device 18 a preferably extends along the axis of rotation 24 a through the bearing element 56 a. In particular, the gear mechanism element 58 a of the interface device 18 a has a greater maximum transverse extent perpendicular to the axis of rotation 24 a on a side of the fixing plane 27 a which faces the drive device 14 a than on a side of the fixing plane 27 a which faces the grinding device 12 a, for the purpose of an axial form fit along the axis of rotation 24 a with the bearing element 56 a. The fan 66 a of the grinding device 12 a is preferably arranged on the gear mechanism element 58 a of the interface device 18 a, in particular for centric rotation about the axis of rotation 24 a. The fan 66 a is not illustrated in FIG. 4 in order to ensure that an inner wall 70 a of the main shells 46 a, 48 a can be seen. The fan 66 a has an asymmetrical form for the purpose of forming a gear mechanism element of the grinding device 12 a. In particular, the fan 66 a forms the eccentric. In particular, the fan 66 a has a disk-shaped base plate, which is in particular solid, and to which the blading of the fan 66 a is fastened. The base plate preferably faces the docking interface 22 a and is arranged in particular in the same plane perpendicular to the axis of rotation 24 a as the additional fixing elements 150 a, 152 a. The blading of the fan 66 a preferably faces the grinding pad 132 a. In particular, as eccentric the fan 66 a has a central shank, which is surrounded by the blading in a plane which is perpendicular to the axis of rotation 24 a. In particular, the central shaft is arranged on the base plate eccentrically in relation to the base plate. The gear mechanism element 58 a of the interface device 18 a preferably engages in the central shank, forming the eccentric, of the fan 66 a and is connected to it in particular for rotation therewith (cf. FIG. 6). The fan 66 a preferably has at least one fan counterbalance 148 a, which is arranged inside the blading. In particular, a shape of the fan counterbalance 148 a is matched to a shape of the blading. The base plate of the fan 66 preferably has a recess 162 a, which is arranged offset with respect to the rest of the base plate in the direction of the axis of rotation 24 a. The recess 162 a is in the form in particular of a half-ring. The recess 162 a and the fan counterbalance 148 a, in particular together with part of the blading, are preferably arranged on the recess 162 a. In a section of the fan 66 a along a plane encompassing the axis of rotation 24 a, the recess 162 a and the fan counterbalance 148 a are arranged in particular in a half of the fan 66 a which comprises a smaller volume fraction of the central shank which is in the form of an eccentric. A height of the blading on the recess 162 a parallel to the axis of rotation 24 a is preferably smaller than a height of the rest of the part of the blading, in particular with the result that the entire blading of the fan 66 a has a common termination plane which is perpendicular to the axis of rotation 24 a. The drive fan 64 a of the drive device 14 a and the fan 66 a of the grinding device 12 a are arranged on different sides of the axial form-fitting element 28 a, 29 a, 30 a, 32 a in the direction of the axis of rotation 24 a. In particular, at the boundary the docking interface 22 a terminates a receiving space of the drive housing 16 a in which the drive fan 64 a is arranged. In particular, an end of the docking interface 22 a along the axis of rotation 24 a delimits a fan receiving region 68 a, in which the fan 66 a is arranged.

The grinding device 12 a comprises the fan 66 a for the purpose of transporting away material removed during a grinding operation. The inner wall 70 a, which delimits the fan receiving region 68 a, of the connecting housing unit 20 a is in the form of a funnel about the axis of rotation 24 a of the drive shaft 26 a of the drive device 14 a in order to guide an air stream created by the fan 66 a. In particular, the fan receiving region 68 a narrows along the axis of rotation 24 a in the direction of the grinding pad 132 a proceeding from the plane which is perpendicular to the axis of rotation 24 a and in which the additional fixing elements 150 a, 152 a are arranged. The main shells 46 a, 48 a of the connecting housing unit 20 a at least partially surround the fan 66 a in the assembly plane 50 a, which is parallel to the axis of rotation 24 a. In particular, the main shells 46 a, 48 a surround the fan 66 a, in particular the blading thereof, in a direction parallel to the axis of rotation 24 a. In particular, the main shells 46 a, 48 a comprise at least one base portion 180 a, which is arranged between the fan 66 a and the grinding pad 132 a. The connecting housing unit 20 a has an air inlet 74 a. The air inlet 74 a is preferably arranged in the base portion 180 a of the main shells 46 a, 48 a. In particular, the base portion 180 a has a base surface which faces the fan 66 a and runs at least substantially perpendicularly to the axis of rotation 24 a. A maximum transverse extent of the base surface perpendicular to the axis of rotation 24 a is in particular smaller than a maximum transverse extent of the fan 66 a perpendicular to the axis of rotation 24 a. The grinding-pad holder 156 a projects in particular through the air inlet 74 a, in particular without making contact with the main shells 46 a, 48 a. The eccentric bearing 158 a, the gear mechanism element 58 a and/or the eccentric are preferably arranged at least substantially flush with the base portion 180 a of the main shells 46 a, 48 a or are arranged set back in the direction of the drive device 14 a relative to the base portion 180 a.

The inner wall 70 a is segmented in the direction of the axis of rotation 24 a. A mouth opening 78 a in the ejector port 76 a of the connecting housing unit 20 a and the air inlet 74 a of the connecting housing unit 20 a are arranged in different segments of the inner wall 70 a. In particular, the mouth opening 78 a is arranged in an ejector segment 182 a of the connecting housing unit 20 a. The inner wall 70 a runs in the ejector segment 182 a preferably at least substantially parallel to the axis of rotation 24 a. In particular, the ejector segment 182 a is arranged in the plane with the additional fixing elements 150 a, 152 a. The connecting housing unit 20 a preferably comprises at least one guide segment 184 a, which is arranged in the direction of the axis of rotation 24 a between the ejector segment 182 a and the base portion 180 a. The inner wall 70 a runs in the guide segment 184 a in particular at an acute angle to the axis of rotation 24 a. The connecting housing unit 20 a preferably comprises at least one further guide segment 186 a, which is arranged between the guide segment 184 a and the base portion 180 a. In particular, the inner wall 70 a in a further guide segment 186 a has an angle in relation to the axis of rotation 24 a which is larger than the angle of the guide segment 184 a in relation to the axis of rotation 24 a. In particular, the portions of the ejector segment 182 a, the guide segment 184, the further guide segment 186 a and the base portion 180 a and the portion, forming the mating surface, of one of the main shells 46 a, 48 a are formed integrally with one another.

The connecting housing unit 20 a has a conical spiral track 72 a arranged on the inner wall 70 a. The spiral track 72 a leads in particular from the air inlet 74 a of the connecting housing unit 20 a in the direction of the axis of rotation 24 a to the ejector port 76 a of the connecting housing unit 20 a. In particular, the conical spiral track 72 a is arranged in the guide segment 184 a. FIG. 6 shows a cross section, perpendicular to the axis of rotation 24 a, through the ejector segment 182 a. The fan receiving region 68 a preferably has an asymmetrical form. On account of the spiral track 72 a, in a plane which is perpendicular to the axis of rotation 24 a, the inner wall 70 a has in particular a spacing from the axis of rotation 24 a which is dependent on an angular position with respect to the axis of rotation 24 a. The mouth opening 78 a of the ejector port 76 a, together with the inner wall 70, in particular forms a separating edge 82 a, which runs at least substantially parallel to the axis of rotation 24 a. The spacing between the inner wall 70 a and the axis of rotation 24 a is preferably at its smallest at the separating edge 82 a. The spacing between the inner wall 70 a and the axis of rotation 24 a preferably increases continuously or remains constant in sections. The spacing between the inner wall 70 a and the axis of rotation 24 a particularly preferably increases linearly with an angular difference in relation to an angular position of the separating edge 82 a, illustrated here in particular in the clockwise direction. The spiral track 72 a is optionally formed in only one of the main shells 48 a, while the spacing of the guide segments 184 a is kept constant in sections in the main shell 46 a with the ejector port 76 a. The conical spiral track 72 a preferably has a pitch parallel to the axis of rotation 24 a which leads in at most one revolution, preferably a half-revolution, from the further guide segment 186 a to the mouth opening 78 a. The guide segment 184 a, forming the spiral track 72 a, of the inner wall 70 a has an angle of between 25 and 40°, preferably between 30° and 35°, in relation to the axis of rotation 24 a in a plane which encompasses the axis of rotation 24.

The spiral track 72 a, in particular the guide segment 184 a, in a projection along the axis of rotation 24 a preferably has no overlap with the fan 66 a. More than 50%, in particular more than 75%, preferably more than 90%, of the further guide segment 184 a in a projection along the axis of rotation 24 a is arranged inside the fan 66 a. The blading of the fan 66 a has a bevel 86 a (see FIG. 3). The bevel 86 a is arranged transversely to the axis of rotation 24 a and at least substantially parallel to the further guide segment 186 a of the inner wall 70 a. The inner wall 70 a in the further guide segment 186 a and in particular the bevel 86 a preferably has an angle in relation to the axis of rotation 24 a in a plane which encompasses the axis of rotation 24 a of between 50° and 70°, in particular between 55° and 65°.

A further separating edge 80 a, which is formed by the mouth opening 78 a of the ejector port 76 a of the connecting housing unit 20 a, runs at least substantially perpendicularly to the axis of rotation 24 a. In particular, the further separating edge 80 a separates the ejector segment 182 a from the guide segment 184 a. The further separating edge 80 a continues in particular the spiral path 72 a in the region of the mouth opening 78 a as far as the separating edge 82 a with a constant spacing from the axis of rotation 24 a. The further separating edge 80 a is arranged in particular at a height along the axis of rotation 24 a between the base plate of the fan 66 a and the termination plane of the blading. The separating edge 82 a, which is formed by the mouth opening 78 a of the ejector port 76 a of the connecting housing unit 20 a and runs at least substantially parallel to the axis of rotation 24 a, has a tapering form and has a radius of curvature of less than 10 mm, preferably of less than 3 mm, particularly preferably of less than 2 mm. The radius of curvature of the separating edge 82 a is in particular in a plane which is perpendicular to the axis of rotation 24 a. The radius of curvature of the separating edge 82 a, in particular independently of a precise shaping of the separating edge 82 a, describes a smallest imaginary circle, which rests against both the inner wall 70 a which faces the fan 66 a and an inner wall of the ejector port 76 a. Tangents which rest against the inner wall 70 a and the inner wall of the ejector port 76 a preferably form an angle of between 45° and 65°, preferably between 55° and 60°, in a plane which is perpendicular to the axis of rotation 24 a.

The channel longitudinal axis 84 a runs centrally through an ejector port 76 a and predefines in particular a main flow direction of air through the ejector port 76 a. A projection of the channel longitudinal axis 84 a along the axis of rotation 24 a preferably rests tangentially on an outer contour of the fan 66 a. The projection of the channel longitudinal axis 84 a along the axis of rotation 24 a preferably forms an angle of between 40° and 50°, particularly preferably between 44° and 46°, in relation to the assembly plane 50 a. An inner wall, situated opposite the separating edge 82 a, of the ejector port 76 a extends preferably from the assembly plane 50 a to an ejector opening of the ejector port 76 a, wherein a spacing between this inner wall and the axis of rotation 24 a in the assembly plane 50 a is matched to the spacing of the spiral track 72 a and becomes continuously greater in the direction of the ejector opening. The channel longitudinal axis 84 a of the ejector port 76 a of the connecting housing unit 20 a forms an acute angle, in particular between 15° and 35°, preferably between 20° and 30°with a plane which is perpendicular to the axis of rotation 24 a. The channel longitudinal axis 84 a is inclined away from the grinding device 12 a in the direction of the axis of rotation 24 a, in particular proceeding from the mouth opening 78 a. At the mouth opening 78 a, the ejector port 76 a has in particular a rectangular cross section perpendicular to the channel longitudinal axis 84 a. At the ejector opening, the ejector port 76 a preferably has a circular cross section perpendicular to the channel longitudinal axis 84 a. A protective device 146 a, in particular in the form of webs parallel to the channel longitudinal axis 84 a, for preventing a finger and/or other foreign bodies from entering the ejector port 76 a is preferably arranged in a portion of the ejector port 76 a that has the rectangular cross section.

In particular, the material collection device 116 a is arranged on the region of the ejector port 76 a with the circular cross section. The material collection container 112 a has at least one opening 120 a for feeding the material into the material collection container 112 a. The opening 120 a of the material collection container 112 a is arranged in an opening plane 122 a. The opening plane 122 a preferably can be aligned at least substantially perpendicularly to the longitudinal axis 92 a in at least one state of the material collection device 116 a in which it is arranged at the ejector port 76 a. The material collection container 112 a preferably comprises exactly one opening 120 a in the opening plane 122 a. As an alternative, the material collection device 116 a in the opening plane 122 a comprises a structural element, which divides the opening 120 a into small partial openings. The container longitudinal axis 114 a of the material collection container 112 a is preferably aligned at least substantially perpendicularly to the opening plane 122 a. In particular, the material collection container 112 a has the largest longitudinal extent parallel to, in particular along, the container longitudinal axis 114 a. In particular, the material collection container 112 a has a rotationally symmetrical form about the container longitudinal axis 114 a.

The material collection device 116 a comprises at least one assembly unit 124 a for assembling the material collection container 112 a on the hand-held grinding machine 10 a. The assembly unit 124 a comprises a channel element 126 a for connection to the ejector port 76 a of the hand-held grinding machine 10 a. The channel element 126 a is provided in particular to be arranged concentrically at the ejector port 76 a and has the same channel longitudinal axis 84 a as the ejector port 76 a in a state in which it is arranged on the ejector port 76 a. The channel longitudinal axis 84 a of the channel element 126 a is arranged transversely to the opening plane 122 a of the material collection container 112 a in at least one sectional plane running perpendicularly to the opening plane 122 a. The channel longitudinal axis 84 a is arranged transversely to the opening plane 122 a in a further sectional plane which is perpendicular to the sectional plane and the opening plane 122 a. In particular, the channel longitudinal axis 84 a and the container longitudinal axis 114 a are arranged in a skewed manner. The sectional plane in a configuration shown perpendicularly to the axis of rotation 24 a can be seen in FIG. 6. FIG. 7 shows the further sectional plane, which is illustrated here in particular offset to the container longitudinal axis 114 a. In the state of the material collection device in which it is assembled on the hand-held grinding machine, the container longitudinal axis 114 a can be aligned at least substantially parallel to the assembly plane 50 a, in particular wherein the container longitudinal axis 114 a is aligned parallel to the longitudinal axis 92 a. When the container longitudinal axis 114 a is aligned parallel to the longitudinal axis 92 a, the further sectional plane is arranged in particular parallel to the assembly plane 50 a. The container longitudinal axis 114 a of the material collection container 112 a forms, relative to the assembly plane 50 a, an angle which, when added to an angle between the channel longitudinal axis 84 a and the container longitudinal axis 114 a, forms a total angle of between 80° and 100°, particularly preferably of 90°. In particular, the channel longitudinal axis 84 a intersects the opening plane 122 a in the sectional plane at an angle of between 40° and 50°, preferably between 44° and 46°. In particular, the channel longitudinal axis 84 a intersects the opening plane 122 a in the further sectional plane at an angle of between 15° and 30°.

The channel element 126 a is preferably plugged onto the ejector port 76 a along the channel longitudinal axis 84 a. An inner wall of the channel element 126 a and/or an outer wall of the ejector port 76 a preferably has structural elements for the purpose of a force fit, which in particular can be released and established by hand, of the channel element 126 a with the ejector port 76 a, for example webs or nubs with an interference fit and/or a sheathing with an elastic material or the like. The material collection device 116 a is preferably arranged on the ejector port 76 a such that it can rotate, in particular at least with a moderate expenditure of force. In particular, the moderate expenditure of force necessary for rotating the material collection device 116 a at the ejector port 76 a exceeds a weight of the material collection device 116 a, in particular in a state of the material collection container 112 a in which it is filled with material removed by the grinding device 12 a. The moderate expenditure of force can preferably be applied by a hand without a tool, in particular smaller than 200N, preferably smaller than 125 N, particularly preferably smaller than 75 N. In particular, the material collection device 116 a remains in a current rotational position with respect to the ejector port 76 a without manual actuation. A rotation of the material collection device 116 a about the channel longitudinal axis 84 a causes a relative position of the container longitudinal axis 114 a in relation to the axis of rotation 24 a and/or of the longitudinal axis 92 a to change. In particular, the material collection device 116 a is arranged pivotably on the ejector port 76 a relative to the drive housing 16 a. This makes it possible to advantageously flexibly align the material collection device 116 a during the grinding operation such that even surfaces which are difficult to access can be processed.

The assembly unit 124 a comprises an adapter housing 128 a. The adapter housing 128 a has an asymmetrically tapering form from the opening plane 122 a in the direction of the channel longitudinal axis 84 a. The channel element 126 a projects at least partially into the adapter housing 128 a. The channel element 126 a has an in particular rotationally symmetrical form in relation to the longitudinal axis 92 a. The channel element 126 a is preferably recessed completely in the adapter housing 128 a. The channel element 126 a and the adapter housing 128 a are particularly preferably formed in one piece. The adapter housing 128 a preferably has an assembly element for fixing the material collection container 112 a to the adapter housing 128 a. For example, the assembly element is in the form of a thread, preferably an external thread. In particular, the material collection container 112 a has an air-permeable container region 168 a for collecting the removed material and a fastening ring 164 a for fastening the container region 168 a to the assembly unit 124 a. The fastening ring 164 a preferably has an assembly element, for example a thread, in particular an internal thread, for connection to the adapter housing 128 a. The container region 168 a is preferably fixed to the fastening ring 164 a by means of a latching and/or screw connection 166 a. In particular, the fastening ring 164 a delimits the opening 120 a. The fastening ring 164 a and the adapter housing 128 a are preferably arranged at least substantially flush with one another. The adapter housing 128 a is in particular in the form of a truncated cone which rests on the fastening ring 164 a in a skewed manner and the cone axis of which is aligned coaxially with the channel longitudinal axis 84 a. A radius of a top surface of the frustoconical adapter housing 128 a is preferably the same as an outer radius of the channel element 126 a.

A maximum adapter longitudinal extent of a portion of the assembly unit 124 a that projects beyond the material collection container 112 a in a direction of the container longitudinal axis 114 a is at least substantially the same as a maximum adapter transverse extent of the assembly unit 124 a in the opening plane 122 a. In particular, a ratio of the adapter longitudinal extent to the adapter transverse extent is between 50% and 80%, preferably between 60% and 70%. In particular, the adapter housing 128 a, in particular an inlet opening 130 a of the channel element 126 a, projects at most slightly beyond the material collection container 112 a in a projection along the container longitudinal axis 114 a. In particular, a projection of the adapter housing 128 a along the container longitudinal axis 114 a is completely inside a smallest imaginary square which specifically completely encloses a projection of the material collection container 112 a. In particular, a maximum distance of the inlet opening 130 a from the container longitudinal axis 114 a is smaller than √2 times an outer radius of the material collection container 112 a in the opening plane 122 a. In FIG. 6, the material collection container 112 a is divided by the sectional plane in a ratio of more than 1:4, and therefore here the diameter of the material collection container 112 a is not illustrated and the adapter housing 128 a only seemingly projects significantly beyond the material collection container 112 a in the direction of the grinding device 12 a.

The outlet opening of the channel element 126 a assumes a maximum outlet opening width between 35% and 55%, in particular between 44% and 47%, of a maximum opening width of the opening 120 a in the opening plane 122 a. A ratio of an internal diameter of the channel element 126 a compared to the opening width of the opening 120 a preferably amounts to between 35% and 60%, preferably between 45% and 55%. The container longitudinal axis 114 a preferably runs through an outlet opening, facing the material collection container 112 a, of the channel element 126 a. The outlet opening in the channel element 126 a is preferably arranged in a plane which runs at least substantially perpendicularly to the channel longitudinal axis 84 a and transversely to the opening plane 122 a. A geometric center point of the outlet opening in the channel element 126 a is arranged offset at least in the further sectional plane in particular with respect to the container longitudinal axis 114 a, in particular by a magnitude of 10% to 30% of the maximum opening width.

The inlet opening 130 a of the channel element 126 a extends in a plane which runs at least substantially perpendicular to the channel longitudinal axis 84 a and in particular transversely to the opening plane 122 a. The inlet opening 130 a engages in particular around the region of the ejector port 76 a with the circular cross section. The ejector port 76 a preferably projects into the channel element 126 a at least as far as the container longitudinal axis 114 a. The inlet opening 130 a in the channel element 126 a is arranged spaced apart from the container longitudinal axis 114 a, running perpendicularly to the opening plane 122 a, of the material collection container 112 a.

FIG. 8 shows a flow diagram of a method 170 a for assembling the hand-held grinding machine 10 a. The method 170 a comprises in particular a preassembly step 172 a. The method 170 a preferably comprises a connection step 174 a. The method 170 a preferably comprises a main-shell arrangement step 176 a. In particular, the method 170 a comprises a fixation step 178 a. In the preassembly step 172 a, in particular the drive device 14 a and/or the grinding device 12 a are preassembled, in particular independently of one another. In the preassembly step 172 a, the drive device 14 a is arranged in the drive housing 16 a, in particular in a half-shell to be assembled of the drive housing 16 a, of the hand-held grinding machine 10 a. In the connection step 174 a, the gear mechanism element 58 a is preferably pressed onto the drive shaft 26 a. In the connection step 174 a, the grinding device 12 a is preferably screwed on the gear mechanism element 58 a. In the main-shell arrangement step 176 a, a form fit, parallel to the axis of rotation 24 a, of the connecting housing unit 20 a with the docking interface 22 a is formed by means of the axial form-fitting element 28 a, 29 a, 30 a, 32 a, arranged in the fixing plane 27 a, of the docking interface 22 a. In the main-shell arrangement step 176 a, the connecting housing unit 20 a is arranged on the docking interface 22 a so as to engage around the docking interface 22 a in the fixing plane 27 a which is perpendicular to the axis of rotation 24 a. In particular, in the main-shell arrangement step 176 a, the main shells 46 a, 48 a are placed on the docking interface 22 a. In particular, the mating surfaces of the main shells 46 a, 48 a are placed onto the contact surface 52 a, wherein the grinding device 12 a is arranged at least partially in the connecting housing portion 20 a. In the main-shell arrangement step 176 a, the sleeve of the main shells 46 a, 48 a is preferably plugged in the fixing recesses 34 a, 36 a in the docking interface 22 a. The main shells 46 a, 48 a are placed against one another in particular in the assembly plane 50 a. In the fixation step 178 a, the separately formed fixing element 42 a, 44 a is arranged in the sleeve arranged in the fixing recess 34 a, 36 a and as a result presses the main shells 46 a, 48 a against one another and in particular the contact surface 52 a against the docking interface 22 a. The fixing elements 42 a, 44 a, the additional fixing elements 150 a, 152 and optionally drive housing fixing elements for connecting the half-shells to be assembled of the drive housing 16 a are preferably assembled on the main shells 46 a, 48 a, the docking interface 22 a and/or the drive housing 16 a in all cases from the same, single direction which is at least substantially perpendicular to the assembly plane 50 a.

FIGS. 9 to 14 show further exemplary embodiments of the disclosure. The following descriptions and the drawings are substantially restricted to the differences between the exemplary embodiments, it being possible to make reference fundamentally also to the drawings and/or the description of the other exemplary embodiments, in particular FIGS. 1 to 8, with respect to components with the same designation, in particular with respect to components with the same reference signs. In order to make a distinction between the exemplary embodiments, the letter a is appended to the reference signs of the exemplary embodiment in FIGS. 1 to 8. The letter a is replaced by letters b to d in the exemplary embodiments in FIGS. 9 to 14. FIG. 9 shows an external view and FIG. 10 shows a longitudinal section of a hand-held grinding machine 10 b in the form of an eccentric grinder. The hand-held grinding machine 10 b comprises a grinding device 12 b, which is in particular identical to the grinding device 12 a of the previous exemplary embodiment. The hand-held grinding machine 10 b has a drive device 14 b, in particular with an electric motor 134 b. In particular, the electric motor 134 b incorporates a rated voltage of 18 volts. An electrical power supply interface 136 b of the drive device 14 b and a longitudinal-axis portion 90 b of a drive housing 16 b of the hand-held grinding machine 10 b is preferably designed for receiving an 18-volt rechargeable battery pack 138 b. The hand-held grinding machine 10 b comprises an interface device 18 b with a docking interface 22 b and a connecting housing unit 20 b. The connecting housing unit 20 b preferably has a counterbalance, which compensates a torque caused by a weight of the rechargeable battery pack 138 b, in particular in order to prevent an axis of rotation 24 b of the drive device 14 b from tilting. The counterbalance is preferably arranged on main shells 46 b, 48 b of the connecting housing unit 20 b, in particular is integrated therein. The main shells 46 b, 48 b are optionally manufactured from metal in order to form the counterbalance, in particular by means of an aluminum/zinc die-casting process. As an alternative, the main shells 46 b, 48 b have metal inclusions in a plastic body as counterbalance. The counterbalance and the electrical power supply interface 136 b are arranged in particular on different sides of a plane which is perpendicular to a longitudinal axis 92 b of the hand-held grinding machine 10 b and contains the axis of rotation 24 b. A portion of the connecting housing unit 20 b with the counterbalance preferably rests against a docking interface 22 b of the interface device 18 b. In particular, the portion of the connecting housing unit 20 b with the counterbalance has a greater wall thickness than a portion of the connecting housing unit 20 b that is arranged on the side situated opposite the plane which is perpendicular to the axis of rotation 92 b and encompasses the axis of rotation 24 b. The portion of the connecting housing unit 20 b with the counterbalance preferably has an outer surface which faces the drive housing 16 b and is inclined in the direction of the grinding device 12 b by 15° to 30° with respect to a plane which is perpendicular to the axis of rotation 24 b. Reference should be made to FIGS. 1 to 8 and the description thereof in terms of further features of the hand-held grinding machine 10 b.

FIG. 11 shows an external view and FIG. 12 shows a longitudinal section of a hand-held grinding machine 10 c. The hand-held grinding machine 10 c has a drive device 14 c and a drive housing 16 c, which are formed in particular identically to the drive device 14 a and the drive housing 16 a, respectively, of the first exemplary embodiment. As an alternative, a grinding device 12 c of the hand-held grinding machine 10 c, in particular without further adaptation, may also be combined with a drive device and a drive housing 16 c, as were shown in the second exemplary embodiment. A grinding pad 132 c of the grinding device 12 c has a diameter of between 70 mm and 80 mm, preferably between 77 mm and 78 mm, for example. In particular, the entire grinding device 12 c and an interface device 18 c of the hand-held grinding machine 10 c in a projection along an axis of rotation 24 c of the drive device 14 c lie inside the drive housing 16 c. A docking interface 22 c of the interface device 18 c is formed in particular identically to the docking interfaces 22 a, 22 b of the previous exemplary embodiments. A connecting housing unit 20 c of the interface device 18 c is adapted in particular to a height of the grinding device 12 c parallel to the axis of rotation 24 c. A maximum transverse extent of the connecting housing unit 20 c perpendicular to the axis of rotation 24 c is preferably insignificantly larger than a maximum transverse extent of the docking interface 22 c, in particular is larger only by a wall thickness, in particular twice the wall thickness, of the connecting housing unit 20 c. In particular, a portion of the connecting housing portion 20 c that runs at least substantially parallel to the axis of rotation 24 c is arranged directly on the docking interface. In particular, additional fixing elements 150 c, 152 c are arranged in a plane parallel to the axis of rotation 24 c with a contact surface 52 c of the docking interface 22 c. A gear mechanism element 58 c of the interface device 18 c engages through an optional fan 66 c along the axis of rotation. In particular, the gear mechanism element 58 c is formed integrally with an eccentric of the grinding device 12 c to form a drive of the grinding pad 132 c. The gear mechanism element 58 c engages around an eccentric bearing 158 c of the grinding device 12 c, in particular in a plane which is perpendicular to the axis of rotation 24 c. The eccentric bearing 158 c preferably engages around a grinding-pad holder 156 c of the grinding device 12 c in a plane which is perpendicular to the axis of rotation 24 c. The grinding-pad holder 156 c receives in particular a continuation of the grinding pad 132 c in a direction parallel to the axis of rotation 24 c.

Reference should be made to FIGS. 1 to 10 and the description thereof in terms of further features of the hand-held grinding machine 10 c.

FIG. 13 shows an external view and FIG. 14 shows a longitudinal section of a hand-held grinding machine 10 d. The hand-held grinding machine 10 d is in the form in particular of an oscillating grinder. The hand-held grinding machine 10 d has a drive device 14 d and a drive housing 16 d, which are formed in particular identically to the drive device 14 a and the drive housing 16 a, respectively, of the first exemplary embodiment. As an alternative, a grinding device 12 d of the hand-held grinding machine 10 d, in particular without further adaptation, may also be combined with a drive device and a drive housing, as are shown in the second exemplary embodiment. A grinding pad 132 d of the grinding device 12 d is fastened to a connecting housing unit 20 d of an interface device 18 d of the hand-held grinding machine 10 d, in particular by means of an elastic mount 160 d. A fan 66 d of the grinding device 12 d is arranged in a fan housing of the grinding device 12 d, which is arranged in particular inside the connecting housing unit 20 d. The elastic mount 160 d is arranged in particular between the fan housing and the connecting housing unit 20 d. A gear mechanism element 58 d of the interface device 18 d is preferably formed integrally with an eccentric of the grinding device 12 d. An eccentric bearing 158 d of the grinding device 12 d engages in particular around the gear mechanism element 58 d in a plane which is perpendicular to an axis of rotation 24 d of the drive device 14 d. The eccentric bearing 158 d is arranged in particular in a guide ring, able to be deflected by the eccentric bearing 158 d, of the grinding pad 132 d and connected to the guide ring preferably in a force-fitting manner. Reference should be made to FIGS. 1 to 12 and the description thereof in terms of further features of the hand-held grinding machine 10 d. 

1. A hand-held grinding machine comprising: at least one grinding device configured to receive or form a grinding apparatus; a drive device configured to drive the grinding device; a drive housing, which receives the drive device; and an interface device configured to operatively connect the grinding device to the drive device, the interface device comprising: at least one connecting housing unit formed separately from the drive housing and the grinding device, the at least one connecting housing configured to at least partially receive the grinding device; and a docking interface arranged on the drive housing, wherein the connecting housing unit engages around the docking interface in a fixing plane which is perpendicular to an axis of rotation of a drive shaft of the drive device, wherein, in the fixing plane, the docking interface comprises at least one axial form-fitting element for forming a form fit with the connecting housing unit parallel to the axis of rotation, and wherein a projection of the at least one axial form-fitting element along the axis of rotation is at least substantially completely inside the drive housing.
 2. The hand-held grinding machine according to claim 1, wherein the axial form-fitting element includes a fixing recess defined in the docking interface.
 3. The hand-held grinding machine according to claim 1, wherein the connecting housing unit has at least two main shells, at least one of which comprises a fixing element formed as a sleeve, which is configured to receive a separately formed fixing element.
 4. The hand-held grinding machine according to claim 1, wherein the at least one axial form-fitting element includes a docking cross section of the docking interface perpendicular to the axis of rotation that tapers along the axis of rotation in a direction away from the grinding device.
 5. The hand-held grinding machine according to claim 1, wherein the at least one axial form-fitting element includes an oblique and/or curved contact surface of the docking interface that runs transversely to the fixing plane and has a form which is complementary to a mating surface of the connecting housing unit.
 6. The hand-held grinding machine according to claim 5, wherein the oblique and/or curved contact surface has a radius of curvature of between 5 mm and 15 mm.
 7. The hand-held grinding machine according to claim 1, wherein the docking interface comprises at least 10% to 20% of an overall height of the drive housing including the docking interface measured parallel to the axis of rotation.
 8. The hand-held grinding machine according to claim 1, wherein the docking interface engages around a bearing element of the drive device in the fixing plane.
 9. The hand-held grinding machine according to claim 1, wherein the at least one axial form-fitting element includes a boundary portion of the docking interface at the drive housing that is at least substantially perpendicular to the axis of rotation, the boundary portion having a smaller cross section than the drive housing such that the connecting housing unit is arrangeable at least substantially flush with the drive housing on the docking interface.
 10. The hand-held grinding machine according to claim 1, wherein the connecting housing unit has at least two main shells, which are aligned against one another in the fixing plane via at least one tongue and groove connection.
 11. The hand-held grinding machine according to claim 1, wherein: the drive device includes a drive fan, the grinding device includes a fan, and the drive fan and the fan are arranged along the axis of rotation on different sides of the axial form-fitting element.
 12. A method for assembling a hand-held grinding comprising: arranging a drive device, which is configured to drive a grinding device that is configured to receive or form a grinding apparatus, in a drive housing of the hand-held grinding machine; at least partially arranging the grinding device in at least one connecting housing unit, which is formed separately from the drive housing and the grinding device, of an interface device that is configured to operatively connect the grinding device to the drive device; arranging the at least one connecting housing unit so as to engage around a docking interface of the interface device, which is arranged on the drive housing, in a fixing plane that is perpendicular to an axis of rotation of a drive shaft of the drive device forming a form fit parallel to the axis of rotation between the connecting housing unit and the docking interface via an axial form-fitting element, which is arranged in the fixing plane, of the docking interface, wherein a projection of the at least one axial form-fitting element along the axis of rotation is at least substantially completely inside the drive housing.
 13. The hand-held grinding machine according to claim 1, wherein the at least one axial form-fitting element is configured as a fixing recess and/or an oblique or concave surface.
 14. The hand-held grinding machine according to claim 2, wherein the fixing recess extends at least substantially parallel to the fixing plane and is configured to receive a fixing element of the connecting housing unit and/or a separately formed fixing element.
 15. The hand-held grinding machine according to claim 3, wherein an overall receiving length of the sleeve corresponds essentially to a length of the separately formed fixing element.
 16. The hand-held grinding machine according to claim 8, wherein the bearing element is configured to rotatably mount a gear mechanism element of the interface device and/or the drive shaft.
 17. The hand-held grinding machine according to claim 10, wherein the tongue and groove connection is curved.
 18. The method according to claim 12, wherein the at least one axial form-fitting element is configured as a fixing recess and/or an oblique or concave surface. 